Up to now, a review is made on an apparatus provided with a sensor that is composed of a strain gauge configured to detect whether the work contacts a contact surface that is to be contacted with the work at a leading end of the finger in a grip mechanism (see PTL 1). For a grip control of the grip mechanism utilizing the sensor, a determination on whether the work is gripped or released is generally carried out by using the detection signal from the sensor. To be more specific, by using a previously set threshold, it is determined that the work is gripped in a case where the detection value based on the detection signal obtained from the sensor is higher than the threshold, and it is determined that the work is released in a case where the detection value is lower than the threshold.
On the other hand, some of industrial-use grip mechanisms include a cover member formed of rubber or the like which is provided on the contact surface that is to be contacted with the work at the finger for avoiding a scratch on the work. In this case, the sensor is covered with the cover member, and force caused by the work is set to be transmitted to the sensor via the cover member. With this cover member, while the scratch on the work is avoided, it is possible to improve a life of the sensor.